Season 1s are great, setup, some payoff, a bit of lead into the overarching story. Then season 2 to X. The heroes win and then lose in the final episode, cliffhanger to next season. People get bored. Final season is announced and they wrap up the show.
Funnily enough, The Boys came to my mind as a negative example. It feels like every season hints at big things coming, but then the finale just kinda resets everything without those big things actually happening. And then the next season starts with them having to get the gang back together again.
I largely enjoyed the most recent season but the finale killed any excitement I might have had for the next season. The finale really avoided resolving anything at all, and basically undid as much as it was possible to undo.